The overall goal of the Protein Identification Core, which will be located within the MS Resource of the Keck Laboratory, will be to identify proteins and their post-translational modifications that are of interest to members of the Neuroproteomics Center and that have been isolated either by individual Center members or by the Protein and Lipid Separation and Profiling Core. In the latter instance, the proteins or peptides of interest may have been determined to be differentially expressed in response to a stimulus or disease based on differential (fluorescence) gel electrophoresis (DIGE) (1), the Beckman-Coulter ProteomeLab PF 2D liquid separation approach (2), or MALDI-MS based biomarker discovery using the algorithm developed by staff in the proposed Bioinformatics and Biostatistics Core (3). In addition to providing existing protein identification technologies to members of the NIDA Neuroproteomies Center, the Protein Identification Core also proposes to extend and improve these technologies.